The biomass, productivity, physiology and grazing pressures of phytoplankton during the polar winter in the Ross Sea region

Phytoplankton samples were obtained from the water column at Cape Armitage and Cape Evans. Phytoplankton chlorophyll biomass was assessed by standard fluorometric methods using filtered samples.

The photosynthesis rate (productivity) and photophysiology of phytoplankton was measured using Water PAM and Microscope PAM to determine maximum quantum yield of fluorescence, the photoadaptive index (Ek), relative electron transfer rate (reIETRmas) and photosynthetic efficiency on cells of common species. This was used to determine which taxa are the most physiological active and which are more able to adapt to the low light conditions of winter.